This is a list of the mammal species
recorded in Thailand. There are 264 mammal species in
Thailand, of which 3 are critically endangered, 11 are
endangered, 24 are vulnerable, and 2 are near-threatened. 1 of the species
listed for Thailand is considered to be extinct.

The order Primates contains all the species commonly
related to the
lemurs,
monkeys, and
apes,
with the latter category including
humans. It is divided informally into three main
groupings:
prosimians, monkeys of the
New World, and monkeys and apes of the
Old World.

Rodents make up the largest order of mammals, with over
40 percent of all mammalian species. They have two
incisors in the upper and lower jaw which grow
continually and must be keep short by gnawing. Most rodents
are small though the
capybara can weigh up to 45 kg (100 lb).

The lagomorphs comprise two families,
Leporidae (hares
and
rabbits), and Ochotonidae (pikas).
Though they can resemble
rodents, and were classified as a
superfamily in that order until the early 20th century, they
have since been considered a separate order. They differ from
rodents in a number of physical characteristics, such as having
four incisors in the upper jaw rather than two.

Bats are mammals of the order Chiroptera karptərə; from the Greek χείρ - cheir, "hand" and πτερόν - pteron,
"wing") whose forelimbs form webbed wings, making them the only mammals
naturally capable of true and sustained flight. By contrast, other
mammals said to fly, such as flying squirrels, gliding possums, and
colugos, glide rather than fly, and can only glide for short distances.
Bats do not flap their entire forelimbs, as birds do, but instead flap
their spread-out digits, which are very long and covered with a thin
membrane or patagium. Bats represent about 20% of all classified mammal
species worldwide, with about 1,240 bat species divided into two
suborders: the less specialized and largely fruit-eating
'megachiroptera', or flying foxes, and the more highly specialized and
echolocating 'microchiroptera'. About 70% of bats are insectivores. Most
of the rest are frugivores, or fruit eaters. A few species, such as the
fish-eating bat, feed from animals other than insects, with the vampire
bats being the only parasitic mammalian species. Bats are present
throughout most of the world, performing vital ecological roles of
pollinating flowers and dispersing fruit seeds. Many tropical plant
species depend entirely on bats for the distribution of their seeds.
Bats are important in eating insect pests, reducing the need for
pesticides. The smallest bat is the Kitti's hog-nosed bat, measuring
29–34 mm (1.14–1.34 in) in length, 15 cm (5.91 in) across the wings and
2–2.6 g (0.07–0.09 oz) in mass. Found only in Thailand, it is
also arguably the smallest extant species of mammal, with the Etruscan
shrew being the other contender. The largest species of bat is the giant
golden-crowned flying fox, which is 336–343 mm (13.23–13.50 in) long,
has a wingspan of 1.6 m (5 ft 3 in) and weighs approximately 1.1–1.2
kg). There are few fossilized remains of bats, as they are terrestrial
and light-boned. An estimated only 12% of the bat fossil record is
complete at the genus level. An Eocene bat, Onychonycteris finneyi, was
found in the 52-million-year-old Green River Formation in Wyoming,
United States, in 2003. It had characteristics indicating it could fly,
yet the well-preserved skeleton showed the cochlea of the inner ear
lacked development needed to support the greater hearing abilities of
modern bats. This provided evidence flight in bats developed well before
echolocation. The team that found the remains of this species, named
Onychonycteris finneyi, recognized it lacked ear and throat features
present not only in echolocating bats today, but also in other known
prehistoric species. Fossil remains of another Eocene bat,
Icaronycteris, were found in 1960. The appearance and flight movement of
bats 52.5 million years ago were different from those of bats today.
Onychonycteris had claws on all five of its fingers, whereas modern bats
have at most two claws appearing on two digits of each hand. It also had
longer hind legs and shorter forearms, similar to climbing mammals that
hang under branches such as sloth's and gibbons. This palm-sized bat had
broad, short wings, suggesting it could not fly as fast or as far as
later bat species. Instead of flapping its wings continuously while
flying, Onychonycteris likely alternated between flaps and glides while
in the air. Such physical characteristics suggest this bat did not fly
as much as modern bats do, rather flying from tree to tree and spending
most of its waking day climbing or hanging on the branches of trees.

The order Cetacea includes whales,
dolphins and
porpoises.
They are the mammals most fully
adapted to aquatic life with a spindle-shaped nearly hairless body,
protected by a thick layer of blubber, and forelimbs and tail modified to
provide propulsion underwater.

The even-toed ungulates areungulateswhose weight is borne about equally by the third and fourth toes, rather than
mostly or entirely by the third as in
perissodactyls. There are about 220 artiodactyl species, including many that
are of great
economicimportance tohumans.